This study proposes a method to fabricate artificial defects that is almost identical to stress corrosion cracking from the viewpoint of electromagnetic nondestructive evalua tions. The key idea is to realize a region having electrical resistance embedded inside a conductive materials using solid state bonding. A rough region is introduced into th e surface of the materials so that the region is partially bonded to realize electrical resistance The validity of the method is demonstrated using type 316L aus...
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Fabrication of imitative stress corrosion cracking specimens suitable for electromagnetic nondestructive evaluations using solid state bonding

This paper proposes a methodology of lift-off measurement using optical system embedded in Eddy Current Testing (ECT) system. Firstly, the influence of lift-off on ECT signal was evaluated. Secondly, both ECT signal with lift-off shifting and the lift-off signal were acquired by means of an ECT probe with an optical displacement sensor. Then two cases of the crack shapes reconstructions were carried out using inverse analysis code. One was computed with taking the measured lift-off into account and t...
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Methodology of Lift-off Measurement Using Optical System in Eddy Current Testing

This study discusses the stress corrosion cracking (SCC) model which improves accuracy of depth sizing of SCCs with eddy current testing (ECT). For this purpose, the factors that influence ECT for SCCs are evaluated. In this study, the crack morpholog y and oxide fillings in SCCs are evaluated. As a first step, SCCs introduced at room temperature and fatigue cracks with oxide fillings are evaluated. To discuss the EC signals of SCCs, SCCs are artificially introduced and their ECT signals are obtain ed. The...
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Evaluation of the influence of crack branching structure and oxide fillings of stress corrosion cracking for depth sizing based on eddy current testing

It is well-known that Cr depletion in Inconel 600 changes its magnetic properties, and there is a possibility that electromagnetic nondestructive evaluation has capability of evaluating sensitization of Inconel 600 quantitatively. In this study, we discuss application of eddy current method to the evaluation. For the purpose, magnetic proper ties of Inconel 600 with different aging times were evaluated by B-H loop analyzer. Results show that some magnetic parameters correlate well with Cr depletion. Focus...
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Evaluation of Sensitization of Inconel 600 Using Eddy Current Method

This study aims at proposing a novel magnetic testing method, eddy current magnetic signature method for evaluation of residual strain in carbon steels. This method characterize the eddy current magnetic signatures that is eddy current signals in an impedance plain during magnetization process. In order to discuss the feasibility of this method, eddy current magnetic signatures of a set of tensile test specimens are investigated. The relationship between eddy current signature and plastic deformation is di...
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Nondestructive Evaluation of Residual Strain in Carbon Steels by Eddy Current Magnetic Signature Method

This paper discusses the possibility of in-situ quantitative evaluation of crack propagation using Eddy Current Monitoring (ECM) system in a Boiling Water Reactor (BWR) environment. For the purpose, ECM experiment was conducted at a System Safety Benchmark Facility (SSBF). The target for the monitoring was a large-scale pipe specimen made of austenitic stainless steels 304L, 316L, and carbon steel STS410, connected by weld joints of nickel based alloy 182 within the SSBF. Slits were prepared at the H...
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Quantitative Monitoring of Crack Propagation in High Temperature Environment Using Eddy Current Testing

In a previous study, authors showed experimentally the correlation between leakage magnetic flux density and irradiation assisted stress corrosion cracking susceptibility of high purity model austenitic stainless ste els. This study aimed to investigate mechanism of the correlation. Tensile test at elevated temperature and aging test were conducted on materials simulating irradiation-induced segregation, and leakage magnetic flux density was measured before and after these tests in order to study the influ...
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Evaluation of Sensitivity to Irradiation Assisted Stress Corrosion Crackingby Measurement of Leakage Magnetic Flux Density

Eddy current testing (ECT) has been widely used for the non-destructive testing of metal structures. ECT has high capability of detecting surface breaking cracks and length sizing in nuclear power plants. However, it is known there is the error in the evaluation of the depth of the crack. Martensitic phase occurs due to the stress of crack in the vicinity of the crack and oxide layer of crack surface can affect the evaluation of crack depth. In this study, we assess the influence that impact these fact...
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Influence of eddy current testing of martensitic phase and oxide fillings in fatigue cracks

This paper proposes a novel concept of the measurement-integrated virtual system aiming at next-gene ration uclear power plants with intelligent system. The present system is composed of wireless sensor s, a measurement-integrated simulator and a lifecycle simulator. Some element research activities to realize the measurement-integrated virtual system are introduced, and future efforts are overviewed....
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Ceasurement-integrated virtual system aiming at next-generation nuclear power plants with intelligent system

In this study, superconducting electromagnetic acoustic transducer (EMAT) is developed to transmit strong ultrasound, which is expected as an experimental tool for mechanism study of nonlinear ultrasound. For the purpose, EMAT experiment is carried out using uniform and strong filed generated by a superconducting magnet, and surface displacement of specimen is measured by a laser Doppler vibrometer. As the result, the linear relationship between the surface displacement and magnetic flux density was co...
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Development of superconducting electromagnetic acoustic transducer system and quantitative evaluation of ultrasound transmission by numerical analysis